2024/10/31日工作總結

mybatis的資料庫連線和mapper代理開發

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package com.itheima.mapper;


import com.itheima.pojo.Brand;

import java.util.List;

public interface BrandMapper {
    public List<Brand>selectAll();
}

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package com.itheima.pojo;

/**
 * 品牌
 *
 * alt + 滑鼠左鍵：整列編輯
 *
 * 在實體類中，基本資料型別建議使用其對應的包裝型別
 */

public class Brand {
    // id 主鍵
    private Integer id;
    // 品牌名稱
    private String brandName;
    // 企業名稱
    private String companyName;
    // 排序欄位
    private Integer ordered;
    // 描述資訊
    private String description;
    // 狀態：0：禁用  1：啟用
    private Integer status;


    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getBrandName() {
        return brandName;
    }

    public void setBrandName(String brandName) {
        this.brandName = brandName;
    }

    public String getCompanyName() {
        return companyName;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    public Integer getOrdered() {
        return ordered;
    }

    public void setOrdered(Integer ordered) {
        this.ordered = ordered;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    @Override
    public String toString() {
        return "Brand{" +
                "id=" + id +
                ", brandName='" + brandName + '\'' +
                ", companyName='" + companyName + '\'' +
                ", ordered=" + ordered +
                ", description='" + description + '\'' +
                ", status=" + status +
                '}';
    }
}

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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.itheima.mapper.BrandMapper">

    <!--
        資料庫表的欄位名稱 和 實體類的屬性名稱 不一樣，不能自動封裝資料
            *起別名
            *resultMap
    -->

    <!--
        id:唯一標識
        type:對映型別，支援別名
    -->
    <resultMap id="brandResultMap" type="brand">
        <!--
            id:主鍵對映
            result:一般欄位

                column:表列名
                property:實體類屬性名
        -->
        <result column="brand_name" property="brandName"/>
        <result column="company_name" property="companyName"/>
    </resultMap>

    <select id="selectAll" resultMap="brandResultMap">
        select *
        from tb_brand;
    </select>

    <!--<select id="selectAll" resultType="brand">
        select id,brand_name as brandName,company_name as companyName,ordered,description,status
        from tb_brand;
    </select>-->
    
    <!--<select id="selectAll" resultType="brand">
        select *
        from tb_brand;
    </select>-->
    
    
</mapper>

點選檢視程式碼

package com.itheima.test;

import com.itheima.mapper.BrandMapper;
import com.itheima.pojo.Brand;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyBatisTest {

    @Test
    public void testSelectAll() throws IOException {
        //1.獲取SqlSessionFactory
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        //2.獲取SqlSession物件
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //3.獲取Mapper介面代理物件
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);

        //4.執行方法
        List<Brand> brands = brandMapper.selectAll();
        System.out.println(brands);

        //5.釋放
        sqlSession.close();


    }
}